Even if there is a certain trouble with an accelerator pedal, e.g. if a driver lays down a floor mat anew and the accelerator pedal should be caught by the newly laid floor mat and cannot be returned from a depressed state by any chance, a vehicle is required to be able to be stopped if a brake pedal is depressed.
Thus, JPH11-148396A discloses to limit an opening of a throttle valve when the operation amount of an accelerator pedal is kept substantially constant for a predetermined time or longer and a brake pedal is depressed.
When driving a vehicle, a driver generally depresses the accelerator pedal and the brake pedal in a distinguishing manner with the right foot. Some drivers may depress the brake pedal with the left foot while depressing the accelerator pedal with the right foot depending on the situation. Thus, the opening of the throttle valve is limited after discriminating whether the driver is intentionally depressing the brake pedal with the left foot or depressing the brake pedal due to a certain trouble having occurred to the accelerator pedal.